How to change English tense? Tell me everything. Thank you.

English * * * has sixteen tenses, which are expressed as follows (taking learning as an example).

Simple continuous tense, perfect continuous tense, perfect continuous tense

I am studying now.

In the past, learning has been learning.

I will study in the future, I will study in the future, and I will always study in the future.

Past and future will learn, learn, learn and learn all the time.

Tense is a verb form that expresses behavior, action and state under various time conditions. So when we say tense structure, we mean the verb form corresponding to tense.

1. Simple present tense

English tenses can be divided into 16: simple present tense, simple past tense, simple future tense, past future tense, and their continuous tense, perfect tense and perfect tense.

Usage: a) indicates the action, situation, state and characteristics that are happening now.

B) idioms.

C) Regular habitual movements.

He always helps others. He always helps others. )

D) objective facts and universal truth. Especially if the context is not the general present tense, it is impossible to keep the tense of the main clause and the clause consistent.

E) indicates the action that will happen according to the regulations, plans or arrangements (limited to some verbs that mean "come, go, move, stop, start, end and continue"). ) can be used with adverbials indicating future time. Common usage is: planes, trains, ships, cars and other means of transportation that run at fixed points on a regular basis.

The next train leaves at 3 o'clock this afternoon.

The next train leaves at 3 o'clock this afternoon. )

How often does this bus run? How often does this bus run? )

F) In the adverbial clauses of time and conditions, the simple present tense (sometimes the present perfect tense) is often used to indicate future events.

When you finish the report, I will have been waiting for about 3 hours. When you finished this report, I had been waiting for nearly three hours. )

2. What are you doing now?

Usage: the action that is going on now.

3. Completed usage: a) indicates that the action has been completed or has just been completed so far.

I bought a new house, but I haven't sold my old one, so I have two houses at present.

A) not sold b) sold c) not sold d) will be sold.

The answer is c) not sold.

B) indicates the action or situation that started from a certain time in the past, continued to the present, and may continue. Progressive verbs are often used at this time. Adverbials of time are often used to indicate a certain point in the past, or a period of time, or the present time.

Although Newton was great, many of his ideas are still modified by the work of contemporary scientists today.

A) being challenged c) being challenged

B) may be challenged d) challenging.

Although Newton was a great man, many of his viewpoints are still challenged today and revised by the work of modern scientists. Challenge is a transitive verb, which should be in passive voice in this sentence; Its action continues to this day, so it is necessary to use the present perfect tense. The answer is c) challenged. A) it's a challenge, and d) it's a challenge. They are all active voices and can't be the answer. B) It may be questioned, although it is in the passive voice, but it is not correct because its meaning is inconsistent with the whole sentence.

C) indicates an action or situation that happened in the past but still has an impact on the present. Some verbs are usually used, such as: arrive, start, find, give, lose, etc.

John broke his left leg. John broke his left leg. )

Note: a) The present perfect tense is the link between the past and the present. The difference between the present perfect tense and the past tense is that the present perfect tense emphasizes the dynamic nature of the action, or is influenced by the dynamic nature, which is the dynamic result and has an impact on the present; The past tense only indicates actions that happened at a specific time in the past, and has nothing to do with the present.

He worked in that hospital for eight years. He used to work in that hospital for eight years. This is just telling a past fact. He is not in the hospital now. )

He worked in that hospital for eight years. He worked in that hospital for eight years. He used to work and still works in that hospital. )

B) Because the completion of the adverbial of time containing for plus a period of time or since plus a time point is dynamic and continuous, terminal verbs or instantaneous verbs cannot be used.

My sister has been married for five years.

My sister is married. Don't disturb her. (terminal verb)

C) The sentence pattern "This is the first/second/third" tense that needs to be completed ... Time is up ... ".

This is the second time that our company's products have been exhibited in the international exhibition. )

D) the two tenses used in the sentence pattern "it is/hasbeen" ... since "both" are correct.

It's been 10 years since I last saw him. )

E) In sentence patterns such as "not earlier than", "almost/hardly when", "before" and "before", when the main sentence needs to be completed.

Up to today, I haven't seen the professor. )

4. What I've been doing.

Usage: indicates that an action started at a certain time in the past, continues or appears repeatedly today, or will continue into the future.

We have been working on this project for over a month. Up to now, we have been working on that project for more than a month. )

Note: Compared with the present perfect tense, the present perfect tense emphasizes that the action or state has been continuous or repeated from the past to the present.

Example: It seems that oil has been flowing out of this pipe for some time. We will have to repair the machine part.

A) it's leaked b) it's leaking.

C) leaking d) leaking all the time

From the context of this question, these two sentences mean: "It seems that this pipeline has been leaking oil for some time, and we will have to disassemble it for maintenance." The second sentence points out the measures to be taken. The first action took place before the second sentence and has continued to this day. So use the present perfect tense or the present perfect continuous tense in the blank space. D) It has been leaked in the present perfect continuous tense, so it is the answer to this question. 1 1% of the candidates chose b) is a mistake. Because this sentence has an adverbial of time for a period of time, it means that the predicate action continues, and the predicate cannot use the present continuous tense, but must use the tense related to the perfect tense. Some candidates chose c) leak or a) leak by mistake. It is because they didn't notice that the second sentence of this question is the general future tense, so the predicate of the first sentence can't be the past tense or the past perfect tense.

5. Simple past tense

Usage: a) indicates an action or situation that happened at some time in the past.

B) Show past habitual actions. Especially the sentence pattern expressed by would/ used to do itself represents the past tense.

The old man will sit on a bench in a quiet park and watch others for hours, doing nothing and not talking to anyone. The old man used to sit on a bench in a quiet park and watch others for hours, doing nothing and not talking to anyone. )

He used to see his mother once a week. He used to see his mother once a week. )

C) Sometimes it can replace the simple present tense to express a smooth, polite, polite and negotiating tone.

I want to ask you if I can borrow your car. Can I borrow your car? )

Do you mind if I sit here? Can I sit here?)

Precautions: a) Pay attention to the collocation of adverbial of time. The adverbial of time in the past tense should be a word or phrase indicating a certain time in the past, such as yesterday, last month, in 1999, two days ago, etc. It should not be used with recent, past 10 year, this month, etc. Because such adverbials of time are related to the present, we should use the present perfect tense or the simple present tense.

B) The negative forms and interrogative forms are special: you can write them correctly. Take the negative form as an example: it can be used without doing it, without doing it, or without doing it.

Being used to doing is often compared with being used to doing something/something. The former means "used to be or"

Used to be ",requiring the addition of the verb prototype; The latter means "habit" and needs to be added with nouns or gerunds.

6. Usage of past perfect tense: indicates the action that has occurred or the state of existence before a certain time or action in the past. It is what we often say: expressing past behavior or state.

Before that, his family had left him for six months.

A) No C) No B) No D) No.

At that time, his family had not heard from him for six months. It can be seen that the action of the predicate verb was completed at a certain moment in the past, so the predicate should use the past perfect tense. The answer is d). In other options: a) I didn't hear it, because the simple past tense only indicates what happened in the past or the state of existence, so it can't be used with the adverbial of time for six months. B) I haven't heard it all the time. The present perfect continuous tense means that the action that has continued to the present or is still going on in the past is inconsistent with the meaning of the question. C) I haven't heard of it. The present perfect tense indicates the action that has taken place from a certain moment in the past to the present. The then in the question only represents a moment in the past, not the present time.

Note: the logical relationship of "past past" is often embodied through context, not necessarily limited by a certain adverbial of time.

Someone was in our room just now, because when we opened the front door, I noticed a burning cigar head on the floor. Someone was in our room just now because when we opened the front door, I noticed a burning cigarette on the floor. )

Although the adverbial of time is just now, it seems that the simple past tense should be used, but the state of "in the room" existed before the past actions of "opening the door" and "paying attention", so the past perfect tense should be used.

7. Past and future tense (will/should be done)

Usage: indicates what will happen from a certain time in the past.

I said on Thursday that I should visit my friends the next day. On Thursday, I said I would visit my friends the next day. )

Precautions: As the past future tense is a combination of the past tense and the future tense, its precautions can refer to the relevant precautions of the past tense and the future tense.

8. Usage of past continuous tense (was/ were doing): a) indicates actions that happened at a certain time in the past.

Example: Mary was listening to light music 10 minutes ago, Mary was listening to light music. )

B) If one of the main sentences guided by adverbials of time such as when and while is the simple past tense, the other sentence is often used in the past continuous tense.

I was washing my hair when you knocked at the front door. )。

Note: For other matters related to the future tense, please refer to the general future tense mentioned below.

9. Simple future tense

Usage: a) The basic structure is will/shall do.

We will give her a handmade glass as a birthday present. We will give her a handmade glass as a birthday present. )

B) Some verbs, such as: arrive, approach, come, do, finish, go, have, leave, open, play, return, sleep, start, stay, etc. Used in the simple continuous tense, usually used with adverbial of time indicating future time, indicating future tense.

My mother will come to see me next week and stay here until May. )

C) When you say "I'm going to … I want to …", you can use being to do.

That's exactly what I want to say. That's just what I want to say. )

D) When it means "soon", you can use be about to do. Emphasize what to do in the near future or immediately.

Don't worry, I'll give you a careful examination. )

E) five usages of e)be to do:

A) means "something will happen or do something as planned."

I will see her in the laboratory on Monday. You are sure to see her in the lab on Monday. )

B) What to do or not to do (the tone is close to that of should, must, should and have to) indicates the imperative and persuasive tone.

Children, you should go to bed and keep quiet. Our guests will arrive in five minutes. Children, you must go to bed and be quiet. Our guests will arrive in five minutes. )

C) What is possible or impossible (close to possible, possible)

Example: How can I repay this debt? How can I afford such a big debt? )

D) It will happen, and it will happen in the future.

I assure you that this matter will be settled as soon as possible. Be patient.

A. Will be taken care of

C. being cared for

The key point of will attended to is that when it means "deal with and solve", attend is an intransitive verb and must be used with to. In addition, from the context, things are obviously not solved, so we should use the passive voice of the future tense. The answer is B.

E) Used in the conditional sentence "If you want to, imagine" (close to if you want to, or if you should)

If food shortage is to be avoided, greater efforts must be made to increase agricultural output.

A) yes, b) yes, c) yes, d) yes.

The answer is a) yes. If we want to avoid food shortage, we must work harder to increase agricultural production.

F) The sentence pattern that can also mean "about to do something" is about to do something.

The coach almost gave up the game because our team scored 7 points. The coach wants to give up the game because the other team has scored seven goals. )

I was about to call him when his letter came.

From a) in b) to c) in d)

The answer is d). At the point of doing, it is a fixed phrases, which means "coming soon". I was about to call him when his letter arrived.

Precautions:

Adverbial clauses guided by conjunctions such as if, when, as, only, after, before, in case, till, till, and adverbs with conjunctions (immediately, the moment, directly) generally use the present tense instead of the future tense. The perfect tense can be used when continuity or dynamics are emphasized.

I hope his health will have improved when you come back next year. I hope his health will be much better when you come back next year. )

10. Future continuous tense (will be done)

Usage: emphasize the action or thing that is happening at a specific time in the future.

Don't worry, you won't miss her. She will be wearing a red T-shirt and a white skirt. Don't worry, you won't miss her. She will wear a red T-shirt and a short white skirt. )

Note: Since this tense is a combination of future tense and continuous tense, please refer to the notes of "General Future Tense" and "Present Continuous Tense" for comments on this tense.

1 1. will be completed.

Usage: indicates an action or state that starts from a future time and continues to another future time, or indicates an action or state that occurs in a future time but has an impact on another future time. It's like translating the present perfect tense into the future time period of the timeline. Its usage has changed from being related to the past and present to being related to the future and the future.

Example: By the end of the meeting, it had lasted a whole week.

A) it must last; b) it will last.

D) it has been going on.

This question examines the tense of predicate verbs. The whole sentence means: "the meeting will last for a whole week from beginning to end." By the time it ends in a sentence, it means that the action will last until some time in the future, so use the future perfect tense. The answer is b) it will continue. If you choose a), because the modal verb must be followed by the perfect tense of the infinitive, indicating a positive speculation about what has happened, and the adverbial of time in this sentence is by the time of end rather than by the time of end, you have made the mistake of not echoing the tense. Although Would can indicate speculation or possibility, would last can't indicate actions that will last until some time in the future, so C) would last is wrong. Because d) completed is the present perfect tense, it means the action that has been completed so far, and it can't mean the action that will continue at some time in the future, so it is also incorrect.

Note: Since this tense is a combination of future tense and perfect tense, please refer to the notes of "General Future Tense" and "Present Perfect Tense" for details of this tense.

12) Future perfect continuous tense: shall have been, will have been.

By the end of next month, this project will have been going on for three years. By the end of next month, this project has been going on for three years. (passive voice)

Before I went home, my 65-year-old son took this old clock apart and repaired it again. Before I got home, my 10-year-old son had taken this old clock apart and put it on several times. It should be emphasized here that the two past actions of "disassembly" and "assembly" have been repeated. (passive voice)

14) Past and future continuous tense: Should be doing, will be doing.

The government promised to build a new highway next July. The government promised to build a new expressway next July. The adverbial of time in this sentence is a specific future time, so it is best to use the future continuous tense. This sentence is in the passive voice.

I believe that by the end of that year, the advanced version of the software should have been developed, but I was wrong. I firmly believe that a new version of the software will be developed before the end of the year. But I was wrong. This sentence is in the passive voice.

16) past and future continuous tense: it should have been done all the time, and it would have been done all the time. For example, they said that the project would have been worked for three years by the end of next month. They said that by the end of the second month, the project had been going on for three years. )